The Democratic Party made history at its national convention Tuesday when it became the first major American political party to endorse marriage equality in its platform, drawing a sharp contrast with the Republican Party’s official stance on the issue.

Delegates approved the platform with its explicit mention of “marriage equality” by voice vote on the floor of the Charlotte Convention Center in North Carolina shortly after 6 p.m. The move was preceded by a rousing speech from platform committee chair Newark Mayor Cory Booker that brought the crowd to its feet.

Advocates who pressed for the inclusion of the plank praised the final vote. The voice affirmation marked the culmination of a process that turned high profile earlier this year when Freedom to Marry launched the Democrats: Say I Do campaign in February. The advocacy also included two rounds of testimony from groups at the draft platform and platform committee meetings this summer.

“Today the Democratic Party stood up for family values and the value of all families by including a freedom to marry plank in its official platform,” said Freedom to Marry founder and president Evan Wolfson in a statement. “The party’s embrace of the freedom to marry matches the sentiment of the American people. They know that that marriage matters, that gay and non-gay loving and committed couples deserve respect, and that strengthening families is part of how we build a stronger country for all.”

Los Angeles Mayor Antonio Villaraigosa, the chair of this year’s Democratic National Convention and a chair of Mayors for the Freedom to Marry, said, “It has been the privilege of a lifetime to hold the gavel at this historic convention. For the first time in history, a major party platform recognizes every American's freedom to marry the person they love as a fundamental right. This is a reflection of our values as a party and what a growing majority of Americans in this country believe.”

The Democratic Party unveiled the document Monday as it prepared for the start of the convention Tuesday, according to the Associated Press. The first night of programming will include a speech from First Lady Michelle Obama, a keynote address from San Antonio Mayor Julian Castro, and a speech from Mary Kay Henry, the lesbian head of the Service Employees International Union (SEIU).

The platform contrasts President Obama and the party’s vision of an economy built from “the middle out” with what it calls Mitt Romney and the Republican Party’s “top down” approach. The document calls the maintenance and growth of the middle class “the defining issue of our time.”

“This election is not simply a choice between two candidates or two political parties, but between two fundamentally different paths for our country and our families,” says the platform.

Part of the difference between the parties includes LGBT civil rights, which are addressed under the Democratic platform’s “Protecting Rights and Freedoms” section. The section includes an endorsement of the Employment Non-discrimination Act, saying that, “People should not be fired based on their sexual orientation or gender identity.”

Prior to moving to the new marriage equality plank, the platform reviews the record of President and the Democratic Party during his first term.

“President Obama and the Democratic Party are committed to ensuring all Americans are treated fairly,” says the document. “This administration hosted the first-ever White House Conference on Bullying Prevention and we must continue our work to prevent vicious bullying of young people and support LGBT youth. The President’s record, from ending “Don’t Ask, Don’t Tell” in full cooperation with our military leadership, to passing the Matthew Shepard and James Byrd Jr. Hate Crimes Prevention Act, to ensuring same-sex couples can visit each other in the hospital, reflects Democrats’ belief that all Americans deserve the same chance to pursue happiness, earn a living, be safe in their communities, serve their country, and take care of the ones they love. The Administration has said that the word ‘family’ in immigration includes LGBT relationships in order to protect bi-national families threatened with deportation.”

The section also includes the new “Freedom to Marry” plank that the platform committee approved unanimously for the first time last month.

“We support the right of all families to have equal respect, responsibilities, and protections under the law,” says the document. “We support marriage equality and support the movement to secure equal treatment under law for same-sex couples. We also support the freedom of churches and religious entities to decide how to administer marriage as a religious sacrament without government interference.”

“We oppose discriminatory federal and state constitutional amendments and other attempts to deny equal protection of the laws to committed same-sex couples who seek the same respect and responsibilities as other married couples,” continues the platform. “We support the full repeal of the so-called Defense of Marriage Act and the passage of the Respect for Marriage Act.”

Despite efforts from gay conservative groups, the Republican Party approved a platform at its convention in Tampa that stridently denounces marriage equality. The document endorses a federal constitutional amendment against same-sex marriage, criticizes the Obama administration for its decision not to defend DOMA from legal challenges, and supports the campaigns underway in the states to pass constitutional amendments against marriage equality.